A conventional ambulance cot is provided with wheels by means of which it may be moved from one place to another, including rolling the cot in and out of an emergency vehicle. In its simplest form, the cot has nonextensible wheels mounted immediately beneath the cot frame. If the cot is to be raised, it must be manually lifted by the attendants.
Several more sophisticated types of ambulance cots are available, one being a elevating type cot wherein the cot frame is mounted on collapsible legs which are arranged to collapse as the cot is placed in the emergency vehicle. Cots of this type have two positions of use, a first or "down" position in which the legs are fully collapsed, and an elevated or "up" position in which the cot frame is at a standard predetermined height for transferring the patient to a bed, operating table or the like. Since such cots have only two positions of use, situations are encountered wherein the cot frame cannot be brought into proper alignment for direct transfer of the patient from a given bed or operating table without requiring the attendants to either raise or lower the patient during transfer.
In another type of elevating cot, the collapsible legs are replaced by an undercarriage connected to the cot frame by means of pivotally mounted cross-forming braces which permitted the cot frame to be raised and lowered to a plurality of intermediate positions between its fully "down" and fully "up" positions of use. Cots of this type must be fully collapsed before being placed in the ambulance which requires the attendants to bear the full weight of the patient while the undercarriage is being collapsed. To overcome this problem, some cots are provided with an extra set of loading wheels projecting forwardly from the cot frame by means of which the forward or head end of the cot may be supported on the floor of the emergency vehicle while the undercarriage is moved to the fully collapsed position. While useful, such additional wheels form obstructions which can impede the maneuverability of the cot in close quarters.
In another type of cot construction, the cot is provided with a base structure which serves as a carrier for a removable stretcher top, thereby providing a multiple purpose cot which can be used either as a conventional ambulance cot, or the stretcher top detached for separate use and reattached to the carrier prior to loading into the emergency vehicle.
While each of the foregoing cots possesses certain desirable features, they also have deficiencies due to the fact that they are designed for specific purposes. A need has arisen for a more versatile ambulance cot which provides a multiplicity of features not heretofore obtainable in a single cot, with particular reference to the ability of the cot to be readily loaded into various types of rescue vehicles, such as ambulances, vans, station wagons, or modular type rescue vehicles having widely differing floor heights.